/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    BinarySparseInstance.java
 *    Copyright (C) 2002-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core;

import java.util.ArrayList;
import java.util.Enumeration;

/**
 * Class for storing a binary-data-only instance as a sparse vector. A sparse
 * instance only requires storage for those attribute values that are non-zero.
 * Since the objective is to reduce storage requirements for datasets with large
 * numbers of default values, this also includes nominal attributes -- the first
 * nominal value (i.e. that which has index 0) will not require explicit
 * storage, so rearrange your nominal attribute value orderings if necessary.
 * Missing values are not supported, and will be treated as 1 (true).
 * 
 * @version $Revision$
 */
public class BinarySparseInstance extends SparseInstance {

    /** for serialization */
    private static final long serialVersionUID = -5297388762342528737L;

    /**
     * Constructor that generates a sparse instance from the given instance.
     * Reference to the dataset is set to null. (ie. the instance doesn't have
     * access to information about the attribute types)
     * 
     * @param instance the instance from which the attribute values and the weight
     *                 are to be copied
     */
    public BinarySparseInstance(Instance instance) {

        m_Weight = instance.weight();
        m_Dataset = null;
        m_NumAttributes = instance.numAttributes();
        if (instance instanceof SparseInstance) {
            m_AttValues = null;
            m_Indices = ((SparseInstance) instance).m_Indices;
        } else {
            int[] tempIndices = new int[instance.numAttributes()];
            int vals = 0;
            for (int i = 0; i < instance.numAttributes(); i++) {
                if (instance.value(i) != 0) {
                    tempIndices[vals] = i;
                    vals++;
                }
            }
            m_AttValues = null;
            m_Indices = new int[vals];
            System.arraycopy(tempIndices, 0, m_Indices, 0, vals);
        }
    }

    /**
     * Constructor that copies the info from the given instance. Reference to the
     * dataset is set to null. (ie. the instance doesn't have access to information
     * about the attribute types)
     * 
     * @param instance the instance from which the attribute info is to be copied
     */
    public BinarySparseInstance(SparseInstance instance) {

        m_AttValues = null;
        m_Indices = instance.m_Indices;
        m_Weight = instance.m_Weight;
        m_NumAttributes = instance.m_NumAttributes;
        m_Dataset = null;
    }

    /**
     * Constructor that generates a sparse instance from the given parameters.
     * Reference to the dataset is set to null. (ie. the instance doesn't have
     * access to information about the attribute types)
     * 
     * @param weight    the instance's weight
     * @param attValues a vector of attribute values
     */
    public BinarySparseInstance(double weight, double[] attValues) {

        m_Weight = weight;
        m_Dataset = null;
        m_NumAttributes = attValues.length;
        int[] tempIndices = new int[m_NumAttributes];
        int vals = 0;
        for (int i = 0; i < m_NumAttributes; i++) {
            if (attValues[i] != 0) {
                tempIndices[vals] = i;
                vals++;
            }
        }
        m_AttValues = null;
        m_Indices = new int[vals];
        System.arraycopy(tempIndices, 0, m_Indices, 0, vals);
    }

    /**
     * Constructor that inititalizes instance variable with given values. Reference
     * to the dataset is set to null. (ie. the instance doesn't have access to
     * information about the attribute types)
     * 
     * @param weight       the instance's weight
     * @param indices      the indices of the given values in the full vector
     * @param maxNumValues the maximium number of values that can be stored
     */
    public BinarySparseInstance(double weight, int[] indices, int maxNumValues) {

        m_AttValues = null;
        m_Indices = indices;
        m_Weight = weight;
        m_NumAttributes = maxNumValues;
        m_Dataset = null;
    }

    /**
     * Constructor of an instance that sets weight to one, all values to 1, and the
     * reference to the dataset to null. (ie. the instance doesn't have access to
     * information about the attribute types)
     * 
     * @param numAttributes the size of the instance
     */
    public BinarySparseInstance(int numAttributes) {

        m_AttValues = null;
        m_NumAttributes = numAttributes;
        m_Indices = new int[numAttributes];
        for (int i = 0; i < m_Indices.length; i++) {
            m_Indices[i] = i;
        }
        m_Weight = 1;
        m_Dataset = null;
    }

    /**
     * Produces a shallow copy of this instance. The copy has access to the same
     * dataset. (if you want to make a copy that doesn't have access to the dataset,
     * use <code>new BinarySparseInstance(instance)</code>
     *
     * @return the shallow copy
     */
    @Override
    public Object copy() {

        BinarySparseInstance result = new BinarySparseInstance(this);
        result.m_Dataset = m_Dataset;
        return result;
    }

    /**
     * Copies the instance but fills up its values based on the given array of
     * doubles. The copy has access to the same dataset.
     *
     * @param values the array with new values
     * @return the new instance
     */
    public Instance copy(double[] values) {

        BinarySparseInstance result = new BinarySparseInstance(this.m_Weight, values);
        result.m_Dataset = m_Dataset;
        return result;
    }

    /**
     * Merges this instance with the given instance and returns the result. Dataset
     * is set to null.
     * 
     * @param inst the instance to be merged with this one
     * @return the merged instances
     */
    @Override
    public Instance mergeInstance(Instance inst) {

        int[] indices = new int[numValues() + inst.numValues()];

        int m = 0;
        for (int j = 0; j < numValues(); j++) {
            indices[m++] = index(j);
        }
        for (int j = 0; j < inst.numValues(); j++) {
            if (inst.valueSparse(j) != 0) {
                indices[m++] = numAttributes() + inst.index(j);
            }
        }

        if (m != indices.length) {
            // Need to truncate
            int[] newInd = new int[m];
            System.arraycopy(indices, 0, newInd, 0, m);
            indices = newInd;
        }
        return new BinarySparseInstance(1.0, indices, numAttributes() + inst.numAttributes());
    }

    /**
     * Does nothing, since we don't support missing values.
     * 
     * @param array containing the means and modes
     */
    @Override
    public void replaceMissingValues(double[] array) {

        // Does nothing, since we don't store missing values.
    }

    /**
     * Sets a specific value in the instance to the given value (internal
     * floating-point format). Performs a deep copy of the vector of attribute
     * values before the value is set.
     * 
     * @param attIndex the attribute's index
     * @param value    the new attribute value (If the corresponding attribute is
     *                 nominal (or a string) then this is the new value's index as a
     *                 double).
     */
    @Override
    public void setValue(int attIndex, double value) {

        int index = locateIndex(attIndex);

        if ((index >= 0) && (m_Indices[index] == attIndex)) {
            if (value == 0) {
                int[] tempIndices = new int[m_Indices.length - 1];
                System.arraycopy(m_Indices, 0, tempIndices, 0, index);
                System.arraycopy(m_Indices, index + 1, tempIndices, index, m_Indices.length - index - 1);
                m_Indices = tempIndices;
            }
        } else {
            if (value != 0) {
                int[] tempIndices = new int[m_Indices.length + 1];
                System.arraycopy(m_Indices, 0, tempIndices, 0, index + 1);
                tempIndices[index + 1] = attIndex;
                System.arraycopy(m_Indices, index + 1, tempIndices, index + 2, m_Indices.length - index - 1);
                m_Indices = tempIndices;
            }
        }
    }

    /**
     * Sets a specific value in the instance to the given value (internal
     * floating-point format). Performs a deep copy of the vector of attribute
     * values before the value is set.
     * 
     * @param indexOfIndex the index of the attribute's index
     * @param value        the new attribute value (If the corresponding attribute
     *                     is nominal (or a string) then this is the new value's
     *                     index as a double).
     */
    @Override
    public void setValueSparse(int indexOfIndex, double value) {

        if (value == 0) {
            int[] tempIndices = new int[m_Indices.length - 1];
            System.arraycopy(m_Indices, 0, tempIndices, 0, indexOfIndex);
            System.arraycopy(m_Indices, indexOfIndex + 1, tempIndices, indexOfIndex, m_Indices.length - indexOfIndex - 1);
            m_Indices = tempIndices;
        }
    }

    /**
     * Returns the values of each attribute as an array of doubles.
     * 
     * @return an array containing all the instance attribute values
     */
    @Override
    public double[] toDoubleArray() {

        double[] newValues = new double[m_NumAttributes];
        for (int i = 0; i < m_Indices.length; i++) {
            newValues[m_Indices[i]] = 1.0;
        }
        return newValues;
    }

    /**
     * Returns the description of one instance in sparse format. If the instance
     * doesn't have access to a dataset, it returns the internal floating-point
     * values. Quotes string values that contain whitespace characters.
     * 
     * @return the instance's description as a string
     */
    @Override
    public String toString() {

        StringBuffer text = new StringBuffer();

        text.append('{');
        for (int i = 0; i < m_Indices.length; i++) {
            if (i > 0) {
                text.append(",");
            }
            if (m_Dataset == null) {
                text.append(m_Indices[i] + " 1");
            } else {
                if (m_Dataset.attribute(m_Indices[i]).isNominal() || m_Dataset.attribute(m_Indices[i]).isString()) {
                    text.append(m_Indices[i] + " " + Utils.quote(m_Dataset.attribute(m_Indices[i]).value(1)));
                } else {
                    text.append(m_Indices[i] + " 1");
                }
            }
        }
        text.append('}');
        if (m_Weight != 1.0) {
            text.append(",{" + Utils.doubleToString(m_Weight, AbstractInstance.s_numericAfterDecimalPoint) + "}");
        }
        return text.toString();
    }

    /**
     * Returns an instance's attribute value in internal format.
     * 
     * @param attIndex the attribute's index
     * @return the specified value as a double (If the corresponding attribute is
     *         nominal (or a string) then it returns the value's index as a double).
     */
    @Override
    public double value(int attIndex) {

        int index = locateIndex(attIndex);
        if ((index >= 0) && (m_Indices[index] == attIndex)) {
            return 1.0;
        } else {
            return 0.0;
        }
    }

    /**
     * Returns an instance's attribute value in internal format. Does exactly the
     * same thing as value() if applied to an Instance.
     * 
     * @param indexOfIndex the index of the attribute's index
     * @return the specified value as a double (If the corresponding attribute is
     *         nominal (or a string) then it returns the value's index as a double).
     */
    @Override
    public final double valueSparse(int indexOfIndex) {

        return 1;
    }

    /**
     * Deletes an attribute at the given position (0 to numAttributes() - 1).
     * 
     * @param position the attribute's position
     */
    @Override
    protected void forceDeleteAttributeAt(int position) {

        int index = locateIndex(position);

        m_NumAttributes--;
        if ((index >= 0) && (m_Indices[index] == position)) {
            int[] tempIndices = new int[m_Indices.length - 1];
            System.arraycopy(m_Indices, 0, tempIndices, 0, index);
            for (int i = index; i < m_Indices.length - 1; i++) {
                tempIndices[i] = m_Indices[i + 1] - 1;
            }
            m_Indices = tempIndices;
        } else {
            int[] tempIndices = new int[m_Indices.length];
            System.arraycopy(m_Indices, 0, tempIndices, 0, index + 1);
            for (int i = index + 1; i < m_Indices.length - 1; i++) {
                tempIndices[i] = m_Indices[i] - 1;
            }
            m_Indices = tempIndices;
        }
    }

    /**
     * Inserts an attribute at the given position (0 to numAttributes()) and sets
     * its value to 1.
     * 
     * @param position the attribute's position
     */
    @Override
    protected void forceInsertAttributeAt(int position) {

        int index = locateIndex(position);

        m_NumAttributes++;
        if ((index >= 0) && (m_Indices[index] == position)) {
            int[] tempIndices = new int[m_Indices.length + 1];
            System.arraycopy(m_Indices, 0, tempIndices, 0, index);
            tempIndices[index] = position;
            for (int i = index; i < m_Indices.length; i++) {
                tempIndices[i + 1] = m_Indices[i] + 1;
            }
            m_Indices = tempIndices;
        } else {
            int[] tempIndices = new int[m_Indices.length + 1];
            System.arraycopy(m_Indices, 0, tempIndices, 0, index + 1);
            tempIndices[index + 1] = position;
            for (int i = index + 1; i < m_Indices.length; i++) {
                tempIndices[i + 1] = m_Indices[i] + 1;
            }
            m_Indices = tempIndices;
        }
    }

    /**
     * Main method for testing this class.
     * 
     * @param options the command line options - ignored
     */
    public static void main(String[] options) {

        try {

            // Create numeric attributes "length" and "weight"
            Attribute length = new Attribute("length");
            Attribute weight = new Attribute("weight");

            // Create vector to hold nominal values "first", "second", "third"
            ArrayList<String> my_nominal_values = new ArrayList<String>(3);
            my_nominal_values.add("first");
            my_nominal_values.add("second");

            // Create nominal attribute "position"
            Attribute position = new Attribute("position", my_nominal_values);

            // Create vector of the above attributes
            ArrayList<Attribute> attributes = new ArrayList<Attribute>(3);
            attributes.add(length);
            attributes.add(weight);
            attributes.add(position);

            // Create the empty dataset "race" with above attributes
            Instances race = new Instances("race", attributes, 0);

            // Make position the class attribute
            race.setClassIndex(position.index());

            // Create empty instance with three attribute values
            BinarySparseInstance inst = new BinarySparseInstance(3);

            // Set instance's values for the attributes "length", "weight", and
            // "position"
            inst.setValue(length, 5.3);
            inst.setValue(weight, 300);
            inst.setValue(position, "first");

            // Set instance's dataset to be the dataset "race"
            inst.setDataset(race);

            // Print the instance
            System.out.println("The instance: " + inst);

            // Print the first attribute
            System.out.println("First attribute: " + inst.attribute(0));

            // Print the class attribute
            System.out.println("Class attribute: " + inst.classAttribute());

            // Print the class index
            System.out.println("Class index: " + inst.classIndex());

            // Say if class is missing
            System.out.println("Class is missing: " + inst.classIsMissing());

            // Print the instance's class value in internal format
            System.out.println("Class value (internal format): " + inst.classValue());

            // Print a shallow copy of this instance
            SparseInstance copy = (SparseInstance) inst.copy();
            System.out.println("Shallow copy: " + copy);

            // Set dataset for shallow copy
            copy.setDataset(inst.dataset());
            System.out.println("Shallow copy with dataset set: " + copy);

            // Print out all values in internal format
            System.out.print("All stored values in internal format: ");
            for (int i = 0; i < inst.numValues(); i++) {
                if (i > 0) {
                    System.out.print(",");
                }
                System.out.print(inst.valueSparse(i));
            }
            System.out.println();

            // Set all values to zero
            System.out.print("All values set to zero: ");
            while (inst.numValues() > 0) {
                inst.setValueSparse(0, 0);
            }
            for (int i = 0; i < inst.numValues(); i++) {
                if (i > 0) {
                    System.out.print(",");
                }
                System.out.print(inst.valueSparse(i));
            }
            System.out.println();

            // Set all values to one
            System.out.print("All values set to one: ");
            for (int i = 0; i < inst.numAttributes(); i++) {
                inst.setValue(i, 1);
            }
            for (int i = 0; i < inst.numValues(); i++) {
                if (i > 0) {
                    System.out.print(",");
                }
                System.out.print(inst.valueSparse(i));
            }
            System.out.println();

            // Unset dataset for copy, delete first attribute, and insert it again
            copy.setDataset(null);
            copy.deleteAttributeAt(0);
            copy.insertAttributeAt(0);
            copy.setDataset(inst.dataset());
            System.out.println("Copy with first attribute deleted and inserted: " + copy);

            // Same for second attribute
            copy.setDataset(null);
            copy.deleteAttributeAt(1);
            copy.insertAttributeAt(1);
            copy.setDataset(inst.dataset());
            System.out.println("Copy with second attribute deleted and inserted: " + copy);

            // Same for last attribute
            copy.setDataset(null);
            copy.deleteAttributeAt(2);
            copy.insertAttributeAt(2);
            copy.setDataset(inst.dataset());
            System.out.println("Copy with third attribute deleted and inserted: " + copy);

            // Enumerate attributes (leaving out the class attribute)
            System.out.println("Enumerating attributes (leaving out class):");
            Enumeration<Attribute> enu = inst.enumerateAttributes();
            while (enu.hasMoreElements()) {
                Attribute att = enu.nextElement();
                System.out.println(att);
            }

            // Headers are equivalent?
            System.out.println("Header of original and copy equivalent: " + inst.equalHeaders(copy));

            // Test for missing values
            System.out.println("Length of copy missing: " + copy.isMissing(length));
            System.out.println("Weight of copy missing: " + copy.isMissing(weight.index()));
            System.out.println("Length of copy missing: " + Utils.isMissingValue(copy.value(length)));

            // Prints number of attributes and classes
            System.out.println("Number of attributes: " + copy.numAttributes());
            System.out.println("Number of classes: " + copy.numClasses());

            // Replace missing values
            double[] meansAndModes = { 2, 3, 0 };
            copy.replaceMissingValues(meansAndModes);
            System.out.println("Copy with missing value replaced: " + copy);

            // Setting and getting values and weights
            copy.setClassMissing();
            System.out.println("Copy with missing class: " + copy);
            copy.setClassValue(0);
            System.out.println("Copy with class value set to first value: " + copy);
            copy.setClassValue("second");
            System.out.println("Copy with class value set to \"second\": " + copy);
            copy.setMissing(1);
            System.out.println("Copy with second attribute set to be missing: " + copy);
            copy.setMissing(length);
            System.out.println("Copy with length set to be missing: " + copy);
            copy.setValue(0, 0);
            System.out.println("Copy with first attribute set to 0: " + copy);
            copy.setValue(weight, 1);
            System.out.println("Copy with weight attribute set to 1: " + copy);
            copy.setValue(position, "second");
            System.out.println("Copy with position set to \"second\": " + copy);
            copy.setValue(2, "first");
            System.out.println("Copy with last attribute set to \"first\": " + copy);
            System.out.println("Current weight of instance copy: " + copy.weight());
            copy.setWeight(2);
            System.out.println("Current weight of instance copy (set to 2): " + copy.weight());
            System.out.println("Last value of copy: " + copy.toString(2));
            System.out.println("Value of position for copy: " + copy.toString(position));
            System.out.println("Last value of copy (internal format): " + copy.value(2));
            System.out.println("Value of position for copy (internal format): " + copy.value(position));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}
